Various film-forming monomers are employed as coating materials and can be cured either thermally or by radiation in the presence of a free radical photoinitiator. Acrylates and methacrylates and vinyl lactams are suitable for this purpose. However, certain vinyl lactam monomers, e.g. N-vinyl caprolactams, alkyl substituted N-vinylpyrrolidones and acrylate oligomers are solids or semi-solid resins which are difficult to handle or to incorporate in reaction mixtures or to provide a uniform distribution of the monomeric or oligomeric species.
Accordingly, it is an object of this invention to provide a liquid reactive diluent for free radical induced radiation polymerizations of polymerizable monomers and oligomers.
Another object of this invention is to provide a reactive diluent which is economically and conveniently prepared from commercially available compounds.
Another object is to provide a reactive diluent capable of modifying the crosslinked density and flexibility of acrylate polymerized coatings.
Still another object is to provide a reactive diluent which is stable against discoloration and which improves adhesion to vinyl surfaces.
Yet another object is to provide a polymerizable diluent system capable of forming a terpolymeric protective coating on a substrate.
Still another object is to provide a process for coating a substrate with an improved protective coating.
These and other objects of this invention will become apparent from the following description and disclosure.